Harm of fine particulate matters to pregnant women

PM2.5 is a particulate matter with a diameter less than 2.5 microns in diameter.
PM2.5 in the air to stay longer, but also more easily into the human respiratory tract,
so the health of pregnant women is more dangerous.  now we can use the particle counter in home.
The study of the pregnant mother with high concentrations of PM2.5 showed that the high concentrations of fine particulate matter may affect the development of embryos.
With the laser particle counter we can clearly know the air quality both for PM2.5 and PM10.
After we know the air quality then we can know how to change it and live in a healthy place.